Tom Rose's Gas Sampling Article

***caveseeker7*** · 29th October 2005, 15:36

Having read Tom’s diving website for quite some time and heard the chatter of his CO2 sampling project in cyberspace I was looking forward to meet the man.

That meeting finally came about at DEMA 2005 in Las Vegas, and timing couldn’t have been better. With patents granted he kindly took the time to explain the project to a couple of people before the Rebreather Party got really started. My thanks again for taking that time I really enjoyed, as well as for publishing your article here at Rebreather World.

This is the thread for feedback, questions and discussion.

A brief background bio of Tom Rose:

Started diving in 1951 .... as he grew up he was greatly influenced by Hans Hass .... in 1961 he built a rebreather in college to push siphons in caves around Blacksburg Virginia where he was an engineering student at VA Tech .... it worked .... he survived .... that all he has to say about that.

In the mid sixties he used an improved rebreather (it couldn't be much easier to build a rebreather than his first one) occasionally when he couldn't get compressed air on a long sabbatical through the islands of the Atlantic and the coast of South America.

His life's work for over 35 years has been air pollution measurement, control, and instrumentation.

He started building and diving rebreathers again about 5 years ago .... and is having a ball.

Tom says he is slightly frustrated in not getting in over 100 dive hours a year anymore but is working on getting back on schedule.

surgeondress · 29th October 2005, 16:44

Has a prototype been built and/or tested already?

Chris

Tom Rose · 29th October 2005, 21:20

Hi Chris,

A bench prototype has been tested for over two years. I have not placed the unit in a rebreather underwater...unless you count the glass of water I held above it....just kidding.... The bench test included a controlable carbon dioxide supply to the loop etc. I will be testing it on one of my homebuilts sometime this winter.

Tom

NickT · 29th October 2005, 22:19

Need any volunteers Tom?
Can you tell me more about the actual CO2 censor? Is this also a design of your own or is it comercially available? To what precision can it detect? I assume it also needs calibration?

Cheers
Nick

Sutty · 30th October 2005, 13:23

Hi Tom,

Sounds very interesting - elegant way of drying the gas!
You state that the device needs no pump but what is producing gas flow? Is it the O2 flow moving the sample gas by venturi/bernouilli effect?

Sounds perfect to add to a Kiss as it has a constant O2 flow.

Regards,
Neil

DanDunfee · 6th November 2005, 09:30

Tom

I unnnerstand the CO2 monitor approach pretty well , and endorsed it s promise as a major step forward in RBs

... even to the US Navy as

you know.

What I don't unnerstand is why you ain't yet signed onto the 'How old

are you ??' thread and poll

Dan

AndyP · 9th November 2005, 16:26

I tried to comment on the article by Tom Rose, but can't so I thought I would post this up here.

The technique Tom has put up can not have a patent on it, certainly in the UK, I know the law is different in the States, but I do not know what the differences are. In the UK if there is provable prior usage i.e. say a scientific paper using the technique then the patent is invalid.

It happens that we ran this as an experiment over here towards the end of last year, in the course of doing so I looked up various papers that described how to do so, there are several where the moisture is removed from air in order to measure CO2, in fact, you have to remove the moisture to use an optical technique for measurement. Tom is totally correct though, it works, and is very accurate, we measured the results using a 1.5M spectrometer and were able to get answers down to nano molear levels. In practical usage though, and this is specific for a rebreather there are some big issues to solve, not least of which the minatureisation of the system.

It is the way to go as far as CO2 monitoring is concerned, sadly, there is a way to go before it is useful, we are still working on it here, we have it down to the size of a shoe box, but it is hard to work out how to get it smaller and keet the accuracy and speed.

Andrew

DanDunfee · 9th December 2005, 06:20

Quote: (Originally Posted by AndyP)

I tried to comment on the article by Tom Rose, but can't so I thought I would post this up here.

The technique Tom has put up can not have a patent on it, certainly in the UK, I know the law is different in the States, but I do not know what the differences are. In the UK if there is provable prior usage i.e. say a scientific paper using the technique then the patent is invalid.

It happens that we ran this as an experiment over here towards the end of last year, in the course of doing so I looked up various papers that described how to do so, there are several where the moisture is removed from air in order to measure CO2, in fact, you have to remove the moisture to use an optical technique for measurement. Tom is totally correct though, it works, and is very accurate, we measured the results using a 1.5M spectrometer and were able to get answers down to nano molear levels. In practical usage though, and this is specific for a rebreather there are some big issues to solve, not least of which the minatureisation of the system.

It is the way to go as far as CO2 monitoring is concerned, sadly, there is a way to go before it is useful, we are still working on it here, we have it down to the size of a shoe box, but it is hard to work out how to get it smaller and keet the accuracy and speed.

Andrew

Andy

Who else do you know of that are working on a CO2 Monitor using approaches similar to Tom Roses ??

Dan

Deepthought · 7th February 2006, 04:22

Hi Guys,

Just wondering about the importance of drying....

From memory, yes, when using Infra Red spectrometers we always dried the sample thoroughly.

But the regions for the O-H bond (as in water) and the C=O bond (as in CO2)were in different parts of the spectrum (Unless this has been changed to comply with EU directives

)

Drying is important if you are interested in a substance which may contain O-H bonds e.g. alcohols.

Surely if you just used a narrow band of wavelengths in the correct region the presence of water would be irrelevant.

Or have I missed the point - Is the water a problem in terms of condensation on the optics?

Andy

jaap · 7th May 2006, 00:52

Quote: (Originally Posted by Deepthought)

Hi Guys,

Just wondering about the importance of drying....

From memory, yes, when using Infra Red spectrometers we always dried the sample thoroughly.

But the regions for the O-H bond (as in water) and the C=O bond (as in CO2)were in different parts of the spectrum (Unless this has been changed to comply with EU directives

)

Drying is important if you are interested in a substance which may contain O-H bonds e.g. alcohols.

Surely if you just used a narrow band of wavelengths in the correct region the presence of water would be irrelevant.

Or have I missed the point - Is the water a problem in terms of condensation on the optics?

Andy

Yes I think the problem is condensation. There are already several rather small CO2 probes using IR, but they all seem limited to non condensing systems.

29th October 2005, 15:36	#1 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,577	Tom Rose's Gas Sampling Article Having read Tom’s diving website for quite some time and heard the chatter of his CO2 sampling project in cyberspace I was looking forward to meet the man. That meeting finally came about at DEMA 2005 in Las Vegas, and timing couldn’t have been better. With patents granted he kindly took the time to explain the project to a couple of people before the Rebreather Party got really started. My thanks again for taking that time I really enjoyed, as well as for publishing your article here at Rebreather World. This is the thread for feedback, questions and discussion. A brief background bio of Tom Rose: Started diving in 1951 .... as he grew up he was greatly influenced by Hans Hass .... in 1961 he built a rebreather in college to push siphons in caves around Blacksburg Virginia where he was an engineering student at VA Tech .... it worked .... he survived .... that all he has to say about that. In the mid sixties he used an improved rebreather (it couldn't be much easier to build a rebreather than his first one) occasionally when he couldn't get compressed air on a long sabbatical through the islands of the Atlantic and the coast of South America. His life's work for over 35 years has been air pollution measurement, control, and instrumentation. He started building and diving rebreathers again about 5 years ago .... and is having a ball. Tom says he is slightly frustrated in not getting in over 100 dive hours a year anymore but is working on getting back on schedule. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
(Offline)

29th October 2005, 16:44	#2 (permalink)
surgeondress New Member Current Rebreather/s: Optima Other Rebreather/s: Join Date: Oct 2005 Location: Shalimar, FL Posts: 38	Re: Tom Rose's Gas Sampling Article Has a prototype been built and/or tested already? Chris
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29th October 2005, 21:20	#3 (permalink)
Tom Rose Still Learning Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Prism Topaz Other CCR Home Build Join Date: Oct 2005 Location: USA,North Carolina Posts: 331	Re: Tom Rose's Gas Sampling Article Hi Chris, A bench prototype has been tested for over two years. I have not placed the unit in a rebreather underwater...unless you count the glass of water I held above it....just kidding.... The bench test included a controlable carbon dioxide supply to the loop etc. I will be testing it on one of my homebuilts sometime this winter. Tom
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29th October 2005, 22:19	#4 (permalink)
NickT Peru Diver Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: May 2005 Location: Peru Posts: 31	Re: Tom Rose's Gas Sampling Article Need any volunteers Tom? Can you tell me more about the actual CO2 censor? Is this also a design of your own or is it comercially available? To what precision can it detect? I assume it also needs calibration? Cheers Nick __________________ NickT Lima, Peru
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30th October 2005, 13:23	#5 (permalink)
Sutty Classic Kiss diver Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: Glossop, Derbyshire, UK Posts: 854	Hi Tom, Sounds very interesting - elegant way of drying the gas! You state that the device needs no pump but what is producing gas flow? Is it the O2 flow moving the sample gas by venturi/bernouilli effect? Sounds perfect to add to a Kiss as it has a constant O2 flow. Regards, Neil
(Online)

6th November 2005, 09:30	#6 (permalink)
DanDunfee Custom Title Allowed! Current Rebreather/s: Other CCR Other SCR Home Build Other Rebreather/s: Not Bought Yet Other CCR Other SCR Home Build Join Date: Sep 2005 Location: Virginia, USA Posts: 204	Re: Tom Rose's Gas Sampling Article Tom I unnnerstand the CO2 monitor approach pretty well , and endorsed it s promise as a major step forward in RBs ... even to the US Navy as you know. What I don't unnerstand is why you ain't yet signed onto the 'How old are you ??' thread and poll Dan
(Offline)

9th November 2005, 16:26	#7 (permalink)
AndyP Mutter Grumble Groan Moan Current Rebreather/s: Inspiration Classic rEvo Other Rebreather/s: rEvo Join Date: Feb 2005 Location: UK Posts: 93	CO2 Monitoring I tried to comment on the article by Tom Rose, but can't so I thought I would post this up here. The technique Tom has put up can not have a patent on it, certainly in the UK, I know the law is different in the States, but I do not know what the differences are. In the UK if there is provable prior usage i.e. say a scientific paper using the technique then the patent is invalid. It happens that we ran this as an experiment over here towards the end of last year, in the course of doing so I looked up various papers that described how to do so, there are several where the moisture is removed from air in order to measure CO2, in fact, you have to remove the moisture to use an optical technique for measurement. Tom is totally correct though, it works, and is very accurate, we measured the results using a 1.5M spectrometer and were able to get answers down to nano molear levels. In practical usage though, and this is specific for a rebreather there are some big issues to solve, not least of which the minatureisation of the system. It is the way to go as far as CO2 monitoring is concerned, sadly, there is a way to go before it is useful, we are still working on it here, we have it down to the size of a shoe box, but it is hard to work out how to get it smaller and keet the accuracy and speed. Andrew
(Offline)

9th December 2005, 06:20	#8 (permalink)
DanDunfee Custom Title Allowed! Current Rebreather/s: Other CCR Other SCR Home Build Other Rebreather/s: Not Bought Yet Other CCR Other SCR Home Build Join Date: Sep 2005 Location: Virginia, USA Posts: 204	Re: CO2 Monitoring Quote: (Originally Posted by AndyP) I tried to comment on the article by Tom Rose, but can't so I thought I would post this up here. The technique Tom has put up can not have a patent on it, certainly in the UK, I know the law is different in the States, but I do not know what the differences are. In the UK if there is provable prior usage i.e. say a scientific paper using the technique then the patent is invalid. It happens that we ran this as an experiment over here towards the end of last year, in the course of doing so I looked up various papers that described how to do so, there are several where the moisture is removed from air in order to measure CO2, in fact, you have to remove the moisture to use an optical technique for measurement. Tom is totally correct though, it works, and is very accurate, we measured the results using a 1.5M spectrometer and were able to get answers down to nano molear levels. In practical usage though, and this is specific for a rebreather there are some big issues to solve, not least of which the minatureisation of the system. It is the way to go as far as CO2 monitoring is concerned, sadly, there is a way to go before it is useful, we are still working on it here, we have it down to the size of a shoe box, but it is hard to work out how to get it smaller and keet the accuracy and speed. Andrew Andy Who else do you know of that are working on a CO2 Monitor using approaches similar to Tom Roses ?? Dan
(Offline)

7th February 2006, 04:22	#9 (permalink)
Deepthought New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jan 2006 Location: York Posts: 24	Re: Tom Rose's Gas Sampling Article Hi Guys, Just wondering about the importance of drying.... From memory, yes, when using Infra Red spectrometers we always dried the sample thoroughly. But the regions for the O-H bond (as in water) and the C=O bond (as in CO2)were in different parts of the spectrum (Unless this has been changed to comply with EU directives ) Drying is important if you are interested in a substance which may contain O-H bonds e.g. alcohols. Surely if you just used a narrow band of wavelengths in the correct region the presence of water would be irrelevant. Or have I missed the point - Is the water a problem in terms of condensation on the optics? Andy
(Offline)

7th May 2006, 00:52	#10 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 480	Re: Tom Rose's Gas Sampling Article Quote: (Originally Posted by Deepthought) Hi Guys, Just wondering about the importance of drying.... From memory, yes, when using Infra Red spectrometers we always dried the sample thoroughly. But the regions for the O-H bond (as in water) and the C=O bond (as in CO2)were in different parts of the spectrum (Unless this has been changed to comply with EU directives ) Drying is important if you are interested in a substance which may contain O-H bonds e.g. alcohols. Surely if you just used a narrow band of wavelengths in the correct region the presence of water would be irrelevant. Or have I missed the point - Is the water a problem in terms of condensation on the optics? Andy Yes I think the problem is condensation. There are already several rather small CO2 probes using IR, but they all seem limited to non condensing systems.
(Online)

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